I’m in a similar boat. Wanting to use TL3 LA barrels (same dimensions as original) on a TL3 SA action.
Just about any machine shop should be able to help. But I ended up picking up a few of these and they’re promising:
McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
www.mcmaster.com
They’re all just ever so slightly thicker than 0.1”, which is good. I just need to take them to a flat stone a little bit and then trim down the outer diameter by putting it in the drill press or maybe router.
A local machine shop is definitely the better route though.